package zuoye2;

import java.util.ArrayList;

public class hw6_at {
	public static void main(String[] args) {
		at();
	}

	private static void at() {
		ArrayList<Integer> arr=new ArrayList<>();
		arr.add(100);
		arr.add(200);
		arr.add(300);
		System.out.print("{");
		for (int i=0;i<arr.size();i++){
			if(i==arr.size()-1){
				System.out.print(arr.get(i));
			}else{
				System.out.print(arr.get(i)+"@");
			}
			
		}
		System.out.print("}");
	}
}
